Took a few days ponder this question, well I know that there are more specific forums to ask this question in any of cryptography perhaps, but as this forum is dedicated to the security indirectly, i decided to ask a few questions here, and are the following:

Well the NSA recommends using AES to encrypt documents "top secret" already which is supposed to be a safe time algorithm. Do not understand it, as it is possible that recommend a cipher that themselves in theory cannot break? That is to say what would happen if someone with bad intentions, such as for example a terrorist encrypt data with this algorithm, as they would defend themselves before such a thing?

From my point of view does not make logical sense, that a security agency recommend something that they themselves cannot break or control.

as it is possible that recommend a cipher that themselves in theory cannot break?

There is no such a thing as "unbreakable" cipher. The whole field of cryptography is more of an engineering discipline than a branch of theoretical mathematics. Until people start proving serious results like P versus NP problem it is just a bit more than a hot air from my mathematician point of view.

The NSA has a dual (or more?) mission. One of those missions is to help protect U.S. interests, commerce etc. For that part of their mission they may make recommendations or help other government agencies technically to help U.S. commerce to have good cryptography available. See the section on the NSA in Scheier's book, Applied Cryptography for more on this.

How trustworthy they are in these positive (from the point of view of those of us wanting privacy, even from them) missions given other conflicting missions, I don't know.

If logical that is of the existence of more algorithms, especially those that were submitted in the contest to choose the new AES.

And from a security standpoint, the winner would be Serpent, but it turns out that they wanted a fast algorithm and with a good implementation in soft-hard.

They never bothered even to create a set of instructions AES-NI, because it wouldn't bother to create such a thing of something violated? But we would go back to what was.

@sacerdos_daemonis

That was some of the reasons for you to start this thread, you said exactly what i think. It is as i think, they create a system, knowing the vulnerabilities and then disseminated, this makes little sense to me, but it is also logical that themselves you have to protect themselves, it is not logical that they violate a algorithm and implement in their departments, since someone could veneficiarse internally.

That is what I would like to think. But that opening the public in this way, is what I find strange.

@Oko

Even if a certain attack was not found effective, but foreign mathematicians, not people who work within said nothing, I hope I am not mistaken.

@thirdm

If you look at that book it has been a little time this well. And good thing is a little as i told a mate above, they even have to be protected internally, because violate please note and that a few know and put themselves in danger.

Another question, Putting more functions in the please note, might break your security, no? Who think?